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makmanalp 19 hours ago [-]
People who love this should consider visiting the Institute and Museum of the History of Science in Florence (now rebranded the Galileo Museum for what I assume are marketing reasons :P).
Agreed, I went in September (we also just wandered into the separate natural history museum in Florence and enjoyed it). It's amazing how beautiful and handcrafted the instruments are. Much more aesthetic than the modern appliance-style instruments used for high-throughput biology (although many hand-built instruments with exposed parts are still cool-looking).
beloch 14 hours ago [-]
"In order to make one of these things work with natural (unenriched) uranium, which was all that they had to work with at the time, they had to get a lot of it situated close together but interspersed with neutron moderators such as pure graphite or heavy water. The Germans just didn’t have enough to make a go of it."
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The Germans tried graphite, but of insufficient purity[1], and concluded heavy water was the only way to go. They "didn't have enough of" that because of allied sabotage efforts[2]. There were some pretty thrilling heroics on display here that would make for a fantastic movie (or historical novel ;) ).
Even had both of these things gone Germany's way in some alternative history, they would still have faced an immense challenge in scaling up their operation under wartime constraints. The scale of the Manhattan project's enrichment efforts was truly colossal.
Im always on the lookout for these kinds of antiques. Many years ago I visited an antique store who were selling a 1916 brunton (geological instrument with compass and clinometer). It now sits amongst my rock collection.
One day I hope to find a late 1800s automatic groundwater datalogger. Think of a seismometer that sits on top of a groundwater well to measure water levels. It would be a dream find for me.
adrian_b 11 hours ago [-]
> This is unenriched uranium—it has the same ratio of U238 to U235 found in all natural samples of the metal. I don’t know what else to say about it except that, as one would expect, it is extraordinarily dense.
Uranium is slightly less dense than gold and tungsten, but the difference is small, so when taken in hand, like in TFA, the sensation should be the same as for gold or tungsten.
There are 6 metals that are denser than gold: osmium, iridium, platinum, rhenium, neptunium and plutonium.
The maximum density of a substance at normal pressure and temperature is not reached in a pure metal, but in a certain alloy of osmium and iridium.
The natural alloy of osmium and iridium, which is found as nuggets in alluvial deposits, together with gold nuggets, is the substance that was originally called "adamant" by the Ancient Greeks. Only many centuries later, after the expedition of Alexander the Great in India, diamonds became known to Europeans and they were named "Indian adamant", hence the modern name "diamond" for them. The original "adamant" was forgotten, and osmium and iridium were rediscovered at the beginning of the 19th century, by separating them from platinum minerals. Platinum is one of the few chemical elements which were not discovered in Europe or Asia, but it was discovered by the natives of South America, long before the contact with Europeans.
It's heaven for science nerds.
Armillary spheres (including a room sized one from the 1500s), all manner of astrolabes, astronomical clocks, hand ground lenses and microscopes and telescopes and Galileo's actual middle finger (https://en.wikipedia.org/wiki/Galileo's_middle_finger), a tabula affinitatum, michelangelo's compasses, even an organum mathematicum!!!!! (https://en.wikipedia.org/wiki/Organum_Mathematicum)
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The Germans tried graphite, but of insufficient purity[1], and concluded heavy water was the only way to go. They "didn't have enough of" that because of allied sabotage efforts[2]. There were some pretty thrilling heroics on display here that would make for a fantastic movie (or historical novel ;) ).
Even had both of these things gone Germany's way in some alternative history, they would still have faced an immense challenge in scaling up their operation under wartime constraints. The scale of the Manhattan project's enrichment efforts was truly colossal.
___________
[1]https://link.springer.com/article/10.1140/epjh/s13129-025-00...
[2]https://en.wikipedia.org/wiki/Norwegian_heavy_water_sabotage
One day I hope to find a late 1800s automatic groundwater datalogger. Think of a seismometer that sits on top of a groundwater well to measure water levels. It would be a dream find for me.
Uranium is slightly less dense than gold and tungsten, but the difference is small, so when taken in hand, like in TFA, the sensation should be the same as for gold or tungsten.
There are 6 metals that are denser than gold: osmium, iridium, platinum, rhenium, neptunium and plutonium.
The maximum density of a substance at normal pressure and temperature is not reached in a pure metal, but in a certain alloy of osmium and iridium.
The natural alloy of osmium and iridium, which is found as nuggets in alluvial deposits, together with gold nuggets, is the substance that was originally called "adamant" by the Ancient Greeks. Only many centuries later, after the expedition of Alexander the Great in India, diamonds became known to Europeans and they were named "Indian adamant", hence the modern name "diamond" for them. The original "adamant" was forgotten, and osmium and iridium were rediscovered at the beginning of the 19th century, by separating them from platinum minerals. Platinum is one of the few chemical elements which were not discovered in Europe or Asia, but it was discovered by the natives of South America, long before the contact with Europeans.